Method for drying wafer at room temperature

Abstract

A method for drying a wafer at room temperature includes a cleaning step, a reacting step and a pressure releasing step. The cleaning step includes putting a processing workpiece into a cleaning solvent. The reacting step includes putting the processing workpiece along with the cleaning solvent into a reaction chamber, implanting a supercritical fluid into the reaction chamber, and increasing a pressure of the reaction chamber to dissolve the cleaning solvent in the supercritical fluid. A critical temperature of the supercritical fluid is below room temperature. The pressure releasing step includes releasing the pressure of the reaction chamber and discharging the supercritical fluid together with the cleaning solvent out of the reaction chamber, after completely dissolving the cleaning solvent in the supercritical fluid.

What is claimed is: 
     
       1. A method for cleaning a FinFET structure on a wafer, comprising:
 a cleaning step including putting a processing workpiece including the FinFET structure into a cleaning solvent; 
 a reacting step including putting the processing workpiece along with the cleaning solvent into a reaction chamber, implanting a supercritical fluid into the reaction chamber, at a flow rate ranging from 10 ml to 200 ml per minute and increasing a pressure of the reaction chamber to dissolve the cleaning solvent in the supercritical fluid, at a temperature from 10° C. to 30° C.; and 
 a pressure releasing step including releasing the pressure of the reaction chamber to be equal to an environmental pressure, and discharging the supercritical fluid together with the cleaning solvent out of the reaction chamber, after completely dissolving the cleaning solvent in the supercritical fluid. 
 
     
     
       2. The method according to  claim 1 , wherein the supercritical fluid is carbon tetrafluoride, nitrogen, argon or hydrogen. 
     
     
       3. The method according to  claim 1 , wherein in the reacting step, the pressure-of the reaction chamber is increased to a range from 300 psi to 30000 psi to dissolve the cleaning solvent in the supercritical fluid. 
     
     
       4. The method according to  claim 1 , wherein the cleaning solvent is isopropanol, acetone, ethanol, or hexane. 
     
     
       5. A method for cleaning a FinFET structure on a wafer, consisted of:
 a cleaning step including putting a processing workpiece including the FinFET structure into a cleaning solvent; 
 a reacting step including putting the processing workpiece along with the cleaning solvent into a reaction chamber, implanting a supercritical fluid into the reaction chamber, at a flow rate ranging from 10 ml to 200 ml per minute and increasing a pressure of the reaction chamber to dissolve the cleaning solvent in the supercritical fluid, at a temperature from 10° C. to 30° C.; and 
 a pressure releasing step including releasing the pressure of the reaction chamber to be equal to an environmental pressure, and discharging the supercritical fluid together with the cleaning solvent out of the reaction chamber, after completely dissolving the cleaning solvent in the supercritical fluid.